Electronic Rechargeable Stylus and Eraser System

ABSTRACT

A system for recording writing performed on a surface includes a rechargeable stylus, a rechargeable eraser, and a charging station for one or both of the rechargeable stylus and the rechargeable eraser. Each of the rechargeable stylus and the rechargeable eraser includes a pair of charging rings. The charging rings are disposed so as to contact a corresponding pair of charging contacts on a receptacle on the charging station for the stylus or the eraser. The receptacle, charging contacts, and charging rings cooperate to charge rechargeable stylus or the rechargeable eraser when the stylus or eraser is placed into the receptacle.

RELATED APPLICATIONS

This application claims priority to the filing date of U.S. ProvisionalApplication No. 61/141,530, filed on Dec. 30, 2008, the entirety ofwhich is hereby incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates generally to a system for recordingwriting performed on a surface. More particularly, the disclosure isdirected to a rechargeable stylus for a system for recording writingperformed on a surface, a rechargeable eraser for a system for recordingwriting performed on a surface, and a charging station for therechargeable stylus and/or the rechargeable eraser.

BACKGROUND

Technologies for capturing and storing handwritten notes includedigitized writing surfaces such as electronic whiteboards and spatialrecognition pens. Typically, electronic whiteboards either photocopy theentire writing surface or serve as the actual input device, recordingthe movements of a pen or stylus along the surface of the board. Spatialrecognition pens record the movement of the pen across a writingsurface, which surface typically must include special marking for thepen to recognize its position. Newer systems track the movement of astylus across any surface using technology embedded in the stylus. Onesuch system, which uses ultrasonic position tracking, is described inU.S. Pat. No. 7,109,979, entitled “System and Method for RecordingWriting Performed on a Surface,” and is hereby incorporated herein byreference. Typically, styli used in such systems, such as that describedin U.S. Pat. No. 6,111,565, entitled “Stylus for Use with TranscriptionSystem,” and hereby incorporated herein by reference, include atransmitter (e.g., an ultrasonic transmitter), which must be suppliedwith a power source. Additional features of similar systems aredescribed in U.S. Pat. Nos. 6,100,877, 6,104,387, 6,124,847, 6,147,681,6,177,927, 6,191,778, 6,211,863, 6,217,686, 6,232,962, 292,180,6,310,615, and 7,109,979, each of which is hereby incorporated herein byreference.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A depicts an exemplary rechargeable stylus system that may be usedwith a system for capturing and digitizing markings on a writingsurface;

FIG. 1B depicts a more detailed view of a portion of the system of FIG.1A;

FIG. 1C illustrates the functionality of the portion of the systemdepicted in FIG. 1B;

FIG. 2 is a cross-sectional view of a rechargeable stylus for use withan exemplary rechargeable stylus system;

FIGS. 3A depicts a cross-sectional view of an alternate embodiment ofthe charging rings used on the rechargeable stylus of FIG. 2;

FIG. 3B depicts a cross-sectional view of an alternate embodiment of thecharging rings used on the rechargeable stylus of FIG. 2;

FIG. 3C depicts an alternate embodiment of charging contacts used on therechargeable stylus of FIG. 2;

FIG. 3D depicts an alternate embodiment of the charging contacts used onthe rechargeable stylus of FIG. 2;

FIG. 4 is a cross-sectional view of a rechargeable eraser for use withan exemplary rechargeable stylus system;

FIG. 5 is a perspective view of a rechargeable stylus, a rechargeableeraser, and a charging tray for recharging the stylus and eraser;

FIGS. 6A depicts an embodiment of a receptacle included in the chargingtray of FIG. 5;

FIG. 6B depicts a perspective view of an embodiment of a receptacleincluded in the charging tray of FIG. 5 and having a curvilinearcross-section;

FIG. 6C depicts a perspective view of an embodiment of a receptacleincluded in the charging tray of FIG. 5 and having a rectangularcross-section;

FIG. 7 depicts a top plan of the recharging tray of FIG. 5;

FIG. 8A depicts an alternate embodiment of a charging contact for use inthe charging tray of FIG. 5;

FIG. 8B depicts a different alternate embodiment of a charging contactfor use in the charging tray of FIG. 5;

FIG. 9A illustrates an embodiment of a rechargeable stylus for use inthe system of FIG. 1;

FIG. 9B illustrates an embodiment of a charging tray receptacle for usewith the rechargeable stylus of FIG. 9A;

FIG. 10A illustrates a second embodiment of a rechargeable stylus foruse in the system of FIG. 1;

FIG. 10B illustrates an embodiment of a charging tray receptacle for usewith the rechargeable stylus of FIG. 10A;

FIG. 100 depicts the rechargeable stylus of FIG. 10A in a differentorientation to illustrate compatibility with the charging trayreceptacle of FIG. 10B;

FIG. 11A illustrates a third embodiment of a rechargeable stylus for usein the system of FIG. 1;

FIG. 11B illustrates an embodiment of a charging tray receptacle for usewith the rechargeable stylus of FIG. 11A;

FIG. 11C depicts the rechargeable stylus of FIG. 11A in a differentorientation to illustrate compatibility with the charging trayreceptacle of FIG. 11B;

FIG. 12 illustrates a rechargeable stylus having mouse functionality;

FIG. 13 illustrates an alternate embodiment of a system for capturingand digitizing movement of a stylus on a writing surface;

FIG. 14A depicts an embodiment of complementary stylus-side and mobiledevice-side coupling circuits in accordance with the embodiment of FIG.13;

FIG. 14B depicts an alternate embodiment of complementary stylus-sideand mobile device-side coupling circuits in accordance with theembodiment of FIG. 13;

FIG. 15 illustrates an alternate embodiment of the system depicted inFIG. 13; and

FIG. 16 illustrates yet another embodiment of the system depicted inFIG. 13.

DETAILED DESCRIPTION

The present disclosure relates to a digitizing system for recordingmovements of a stylus across a surface and, in particular, to arechargeable stylus for use with the system and a charging station forthe stylus. The digitizing system digitizes the movement of the stylusacross the surface by tracking the stylus using signals such as infraredsignals, ultrasonic signals, and the like. The movements of the stylusacross the surface may include the formation or modification of any typeof image by the stylus, including printing, drawings, sketching,erasing, etc. The surface across which the digitizing system tracksmovement of the stylus may be any suitable surface including, but notlimited to, dry erase boards, chalk boards, clipboards, desktops, walls,projection screens, flip chart tablets, and glass panels, regardless ofwhether any of these surfaces is covered by a material such as paper,glass, metal, or plastic, which can be written upon. The surface ispreferably relatively smooth and relatively flat, though the surface mayhave a small degree of curvature.

FIG. 1A illustrates one use of a digitizing system 10. The digitizingsystem 10 includes a tracking and communication unit (TCU) 12, a writingsurface 14, a stylus 16, and a stylus charging station 18. FIG. 1Adepicts the writing surface 14 as a dry erase board (i.e., a“whiteboard”) though, as noted above, the writing surface 14 may be anydesired surface. Although FIG. 1A illustrates the writing surface 14 asa vertical surface, it should be noted that the writing surface 14 couldalso be a horizontal surface, as the orientation of the surface isirrelevant to operation of the digitizing system 10. The digitizingsystem 10 tracks the movements of the stylus 16 across the writingsurface 14. However, it is not necessary that the movement of the stylus16 creates any mark on the writing surface 14 for the system 10 tooperate to digitize the movements of the stylus 16. Moreover, while manyof the embodiments described herein are described with reference to adry erase board such as that depicted in FIG. 1A, and an accompanyingdry erase stylus, the stylus 16 may be any desired stylus. For example,in some embodiments, the stylus 16 operates as a pointing device (e.g.,a mouse) and not a marking device, and the system 10 digitizes themovement of the stylus 16 across a projector screen (not shown), whichallows the system 10 to be used with a computer (not shown) and aprojector (not shown).

In any event, the stylus 16 is preferably wireless, to facilitate easymovement of the stylus 16 across the writing surface 14. As describedbelow, the digitizing system 10 processes signals received from thestylus 16 in order to track the movement of the stylus 16 across thewriting surface 14. Of course, generation of the signals requires atransmitter and a power source for the transmitter. Thus, the stylus 16also includes a battery and, in particular, a rechargeable battery. Thesystem 10 includes the charging tray 18 for this purpose. The stylus 16and the charging tray 18 are described in greater detail below.

Each of the TCU 12 and the charging tray 18 may be mounted to thewriting surface 14, though the charging tray 18 may also be mounted toany convenient surface, as its presence is not strictly required forproper operation of the digitizing system 10. In one embodiment, thewriting surface 14 is a magnetic surface, such as a dry erase board thatincludes a steel plate, and one or both of the TCU 12 and the chargingstation 18 are removably mounted to the writing surface 14 by an arrayof rare earth magnets (not shown). The rare earth magnets preferablyexert a strong magnetic force over a short distance, providingsufficient force to hold the TCU 12 and/or the charging station 18 tothe writing surface 14 (or other surface), but allowing relatively easyremoval of the TCU 12 and/or the charging station 18 from the writingsurface 14 (or other surface). Of course, the TCU 12 and/or the chargingstation 18 may be adhered to the writing surface 14 using any knownmethod including, but not limited to, suction cups, hook-and-loopmaterial, one or more individual magnets, adhesive tape, etc., dependingon the writing surface 14, the permanence of the installation, cost,etc. For example, if the writing surface 14 is a glass window pane,suction cups may be preferable.

FIG. 1B illustrates in greater detail the TCU 12. In the illustratedembodiment, the TCU 12 is a mobile device that tracks the positionand/or movement of the stylus 16 across the writing surface 14 usingultrasonic and infrared signals transmitted by the stylus 16, and alsoreceives additional information about the stylus 16 in the infraredsignal. The TCU 12 includes ultrasonic two sensors 20 and 22 separatedby a fixed distance, D1, and an infrared sensor 24. When the stylus 16is pressed against the writing surface 14, the stylus 16 emits bothinfrared and ultrasonic signals. The infrared sensor 24 receives theinfrared signal, which identifies which stylus touched the surface (thesystem 10 may include numerous styli including, for example, differentcolors of writing styli, styli using different types of writingelements, styli with different width writing tips, a mouse stylus, etc.)using an encoded signal. The infrared signal received by the infraredsensor 24 also indicates to the TCU 12 that the stylus 16 transmitted anultrasonic signal. Meanwhile, the ultrasonic sensors 20 and 22 receivethe ultrasonic signal transmitted by the stylus 16.

FIG. 10 illustrates the concept behind the method used by the TCU 12 totrack the stylus 16. FIG. 1C depicts the stylus 16 at a position, P, onthe writing surface 14. As described above, upon being pressed againstthe writing surface 14, the stylus 16 transmits both an infrared signaland an ultrasonic signal. The infrared signal arrives at the infraredsensor 24 before the ultrasonic signals arrive at the ultrasonic sensors20 and 22 because, of course, light travels faster than sound. Theinfrared signal, in addition to indicating to the TCU 12 which stylus isin contact with the writing surface 14, also activates the ultrasonicsensors 20 and 22. The TCU 12 uses the known time at which the stylus 16transmitted the ultrasonic signals (i.e., the time at which the infraredsensor 24 received the infrared signal) and the time at which each ofthe ultrasonic sensors 20 and 22 received the ultrasonic signal tocalculate the distance between the stylus 16 and the ultrasonic sensors20 and 22. The TCU 12 employs a computer processor (not shown) tocalculate the location of the stylus 16 using basic trigonometricformulas. That is, knowing that the stylus 16 is a distance A from theultrasonic sensor 20 and a distance B from the ultrasonic sensor 22, andknowing that a distance, D1, separates the ultrasonic sensors 20 and 22,the TCU 12 can calculate the angles of the resulting triangle and, bydoing so, the precise location of the stylus 16 on the writing surface14.

One or more styli 16 may be used with the system 10. FIG. 2 illustratesa cross-sectional view of an embodiment of a stylus 16 that can be usedwith the system 10 illustrated in FIG. 1A. As illustrated, the stylus 16includes a tip end 32 and a circuitry end 34. The stylus 16 includes astylus housing 26 forming an elongated body, generally symmetrical abouta lengthwise axis A, that may encompass a writing element 28. FIG. 2depicts a dry erase marker, such as the SANFORD EXPO, as the writingelement 28. However, the stylus 16 may employ any suitable writingelement 28 including, by way of example and not limitation, an inkwell,chalk, a pencil, pencil lead, or a pen. The writing element 28 may havea writing tip 30, such as the tip 30 of the marker illustrated in FIG.2. Alternatively, a non-writing element 28A may replace the writingelement 28 when, for example, a user desires that the stylus 16 notcreate marks on the writing surface 14 (e.g., when the stylus is actingas an input device such as, a mouse or a pointing device, to a computerprojecting a display through a projector onto the writing surface 14,which writing surface 14 may be a projector screen). The non-writingelement 28A may, for example, have an identical form factor to thewriting element 28 (e.g., the dry erase marker), but may substitute forthe writing tip 30 a non-marking tip 30A, such as a Teflon tip formoving along the writing surface 14. Of course, alternate writingelements 28 and non-writing elements 28A with form factors other thanthat illustrated (e.g., pencils, chalk, etc.) may be employed by fittingadaptors (not shown) to the form factor of the illustrated writingelement 28, or by employing alternative embodiments of the stylus 16designed specifically for those alternate writing elements 28.

In any event, the writing element 28 is disposed toward the tip end 32of the stylus 16, with the writing tip 30 of the writing element 28protruding from the housing 26 at the tip end 32. The tip 30 of thewriting element 28 may be enclosed by a cover or cap 36 that mates withthe housing 26. The cap 36 may be formed to have an inner bore 38 and anouter bore 40, such that the inner bore 38 fits securely around a base42 of the tip 30, providing a sealed environment 44 in which the tip 30may be enclosed to prevent the tip 30 from drying out or to protect thetip 30 against damage. The outer bore 40 may provide further isolationof the tip 30 and, additionally, may protect other components of thestylus 16 from damage.

One or more transmitters may be disposed around the base 42 of the tip30. The transmitters may include transmitters of different types and/ortransmitters of the same type and, in one embodiment, include both aninfrared transmitter 43 and an ultrasonic transmitter 46. In someembodiments, the infrared transmitter 43 is protected by a window 45and, in a similar manner, a protection cage 47 may protect theultrasonic transmitter 46. While FIG. 2 depicts the transmitters 43 and46 as situated around the base 42 of the tip 30, the transmitters may belocated in any suitable location on the stylus 16, though locating thetransmitters away from the tip 30 may, in some instances, affect theaccuracy of the resulting digitization.

The housing 26 also includes an electronics sub-assembly 48 at anon-writing end 50 of the writing element 28. The electronicssub-assembly 48 houses a rechargeable power source 52, a switch 53, anindicator light source 54, and various other electronics forcontrolling, among other things, the transmitters 43 and 46. A button 51may allow the separation of the electronics sub-assembly 48 from thehousing 26, to allow access to, or replacement of, the writing element28.

The stylus 16 is activated by pressing the writing element 28 againstthe writing surface 14, which activates the switch 53, and causes therechargeable power source 52 to power the included electronics and thetransmitters 43 and 46. As generally known, the rechargeable powersource 52 may employ any rechargeable battery technology or capacitivestorage solution. In one embodiment, the rechargeable power source 52 isa Lithium-ion battery, though Nickel Zinc batteries, Nickel-Cadmiumbatteries, rechargeable alkaline batteries, Nickel-Metal Hydridebatteries, and Carbon Zinc or Zinc Chloride batteries are all possiblealternatives, and other alternatives exist or may be developed in thefuture.

The rechargeable power source 52 also provides power to the indicatorlight source 54. A light pipe 56 extending from the indicator lightsource 54 to the perimeter of the housing 26, and covered by a cover 57,creates an illuminated ring 58 (when the indicator light source 54 isactive) at the circuitry end 34 of the stylus 16. In one embodiment, theindicator light source 54 and associated light pipe 56 and illuminatedring 58 indicate that the rechargeable power source 52 is charging whenthe stylus 16 is properly placed in the charging station 18. Of course,the indicator light source 54 may, by any means known in the art (e.g.,by flashing one or more patterns, by using a multi-LED light source,etc.), be used for other or additional indications as well, such as toindicate the stylus 16 is fully charged, or to indicate the stylus 16has a low battery. Moreover, while the embodiment illustrated in FIG. 2uses the light pipe 56 to form the illuminated ring 58, otherembodiments may place the indicator light source 54 at the perimeter ofthe housing 26 so that the indicator light source 54 is directlyviewable to a user (e.g., through a window in the housing 26).Additionally, the light pipe 58 may illuminate a logo or other symbol(e.g., a battery symbol) on the stylus 16. In some embodiments, an auralindicator (e.g., a buzzer, speaker, etc.) (not shown) may be includedinstead of, or in addition to, the indicator light source.

The rechargeable power source 52 is electrically connected to twocharging contacts (also referred to herein as charging elements) 60 and62, one of which is connected to each terminal of the rechargeable powersource 52. FIG. 2 depicts an embodiment in which each of the chargingcontacts 60 and 62 forms a metallic ring encircling the stylus 16. Thetwo charging contacts 60 and 62 are disposed toward opposite ends of thehousing 26, with the charging contact 60 disposed toward the tip end 32of the stylus 16, and the charging contact 62 disposed toward thecircuitry end 34 of the stylus 16, adjacent to the indicator ring 58. Aswill be apparent from the remainder of the description, the use ofmetallic rings for the charging contacts 60 and 62 allows the contacts60 and 62 to mate with corresponding charging contacts on the chargingstation 18, regardless of the axial rotation of the stylus 16 therein.Nevertheless, in other embodiments, the charging contacts may take otherforms. For example, in some embodiments, the charging contacts 60 and 62may be incomplete rings such as the incomplete rings 64 and 66illustrated in FIGS. 3A and 3B, respectively. In other embodiments, oneor both of the charging contacts may be a metallic plate 68 disposedalong the length of the housing 26, as depicted in FIG. 3C, or ametallic plate 70 disposed at an end (e.g., the circuitry end 34) of thestylus 16 as depicted in FIG. 3D. In still other embodiments, thecharging contacts 60 and 62 may be disposed in other locations along thelength of the stylus 16, or may include additional charging contacts(not shown in FIG. 2), as described below in further detail. Thecharging contacts 60 and 62 are formed of (or plated with) a conductivematerial, and are preferably formed of (or plated with) a conductive,metallic material that is non-oxidizing, such as Zinc or Nickel, toprevent corrosion.

FIG. 4 illustrates a cross-sectional view of a rechargeable erasingdevice 100 that can also be used with the system 10 illustrated in FIG.1A. The rechargeable erasing device 100 has an erasing pad 108 affixedto an erasing platform 106, and a housing 105 forming an eraser body 103and having an eraser end 102 and a grip end 104. FIG. 4 depicts aneraser pad 108 complementary to the stylus 16 depicted in FIG. 2. Thatis, the eraser pad 108 is a soft, synthetic felt material suitable forremoving dry erase ink from a dry erase board. However, the eraser pad108 may be any material suitable or desired for erasing the markingsleft by the stylus 16. In some embodiments, the eraser pad 108 isreplaceable, to allow replacement of worn eraser pads 108 and/orallowing replacement of an eraser pad 108 of one material with an eraserpad 108 of a different material. In other embodiments, the eraser pad108 and the eraser platform 106 form a replaceable cartridge. Forexample, in either embodiment a first cartridge or pad may include asoft, synthetic felt for use in erasing dry erase ink from a dry eraseboard, while a second cartridge or pad may include a harder felt for useerasing chalk from a chalk board, and a third cartridge or pad mayinclude a Teflon pad for “erasing” part of a projected display (e.g.,when the eraser 100 is acting as an input device to a computerprojecting a display through a projector onto the writing surface 14,which writing surface 14 may be a projector screen).

In any event, the eraser platform 106 is affixed to a force transmissionmember 110. The force transmission member 110 may be formed of anysuitable material (e.g., wood, plastic, metal, etc.), and may be solidor hollow. The force transmission member 110 may cooperate with aretention mechanism 112 that connects the eraser body 103 to the eraserplatform 106. Alternatively, the force transmission member 110 may beformed with a retention mechanism (not shown) for affixing the eraserplatform 106 (or the cartridge) to the eraser body 103.

When the eraser 100 is pressed against the writing surface 14, the forcetransmission member 110 transmits the pressure from the eraser pad 108to the eraser body 103 and, in particular, to a switch 114 locatedwithin the housing 105 of the eraser body 103. As described above withrespect to the stylus 16, activation of the switch 114 causes arechargeable power source 116 to power various electronics andtransmitters and, in particular, one or more infrared transmitters 118(which may be protected by one or more lenses or windows 119) and one ormore ultrasonic transmitters 120. Also like the rechargeable stylus 16,the transmitters 118 and 120 of the rechargeable erasing device 100transmit an infrared signal and an ultrasonic signal, respectively, uponplacement of the eraser pad 108 against the writing surface 14. Theinfrared signal identifies the eraser device 100 to the TCU 12, andindicates to the TCU 12 that the eraser device 100 has transmitted anultrasonic signal. The TCU 12, given the diameter of the eraser pad 108on the eraser device 100, calculates the position of the eraser device100 and uses the information to determine what portion of the writingsurface 14 and, therefore, what portion of the digitized text ordrawing, the user has erased.

Referring still to FIG. 4, the illustrated embodiment of therechargeable eraser 100 includes four infrared transmitters 118 and asingle ultrasonic transmitter 120. It should be apparent that theline-of-sight nature of infrared communications requires that regardlessof the orientation of the eraser 100 when placed against the writingsurface 14, the infrared signal generated by the one or more infraredtransmitters 118 must be directed toward the TCU 12. Thus, depending,among other things, on the shape of the eraser 100, the position of theinfrared transmitters 118, the position of the eraser 100, and thesensitivity of the infrared receiver 24 on the TCU 12, an embodiment ofthe eraser 100 may require (or at least benefit from) multiple infraredtransmitters 118, as depicted in FIG. 4. Where the eraser 100 includesmultiple infrared transmitters 118 the infrared transmitters 118 arepreferably disposed in a symmetric pattern around the perimeter of theeraser 100. For example, the eraser 100 depicted in FIG. 4 illustratesthe eraser 100 with a generally cylindrical body and four infraredtransmitters 118 disposed at 90 degree increments around the axialcenter of the eraser 100.

Similarly, one or more of the ultrasonic transmitters 120 may beemployed on the eraser 100. FIG. 4 depicts an embodiment of the eraser100 having a single ultrasonic transmitter 120 disposed concentricallyaround the force transmission member 110 such that the ultrasonic signaltransmitted from the ultrasonic transmitter 120 propagates radiallyoutward from the axial center of the eraser 100. This arrangement allowsthe ultrasonic receivers 20 and 22 on the TCU 12 to receive theultrasonic signal regardless of the orientation of the eraser 100 whenplaced against the writing surface 14. While some embodiments of thestylus include only a single ultrasonic transmitter 120, otherembodiments may use multiple ultrasonic transmitters 120. For example,one embodiment employs two ultrasonic transmitters 120 operating atdifferent ultrasonic frequencies. This arrangement, when paired with aTCU 12 having ultrasonic sensors 20 and 22 capable of separately sensingeach frequency, or when paired with a TCU 12 having two ultrasonicsensors 20 and two ultrasonic sensors 22, may provide additionalaccuracy as to the position and/or the orientation of the eraser 100.

The eraser 100 further includes two charging contacts 122 and 124, bothof which are disposed on the housing 105 of the body 103, and one ofwhich is connected to each terminal of the rechargeable power source116. Each of the charging contacts 122 and 124 is formed of (or platedwith) a conductive material and, preferably, a non-oxidizing, conductivematerial such as Zinc or Nickel. In the embodiment depicted in FIG. 4,each of the charging contacts 122 and 124 forms a ring around thecircumference of the eraser body 103, to facilitate contact between thecharging contacts 122 and 124 and the corresponding charging contacts onthe charging station 18, regardless of the axial rotation of the eraser100 therein. Of course, the charging contacts 122 and 124 need not forma ring around the circumference of the eraser body 103. Instead, thecharging contacts 122 and 124 may take any form compatible with thecorresponding contacts on the charging station 18, or may be locatedelsewhere on the rechargeable eraser 100.

For example, in one embodiment, one of the charging rings 122 and 124may be disposed on the body 103 of the eraser 100, while the other ofthe charging rings 122 and 124 may be disposed on the eraser platform106 (so long as there is an electrical connection between the chargingring on the eraser platform 106 and the rechargeable power source 116).

In much the same way that the indicator light source 58 and the lightpipe 56 cooperate to form an indicator ring 58 on the stylus 16, theeraser 100 includes an indicator light source 126 that cooperates with alight pipe 128 to form an illuminated ring 130. In one embodiment, theindicator light source 126 and associated light pipe 128 and illuminatedring 130 are used to indicate that the rechargeable power source 116 ischarging when the eraser 100 is properly placed in the charging station18. Of course, the indicator light source 126 may, by any means known inthe art (e.g., by flashing one or more patterns, by using a multi-LEDlight source, etc.), be used for other or additional indications aswell, such as to indicate the eraser 100 is fully charged, or toindicate that the eraser 100 has a low battery. Moreover, while theembodiment illustrated in FIG. 4 uses the light pipe 128 to form theilluminated ring 130, other embodiments may place the indicator lightsource 126 at the perimeter of the housing 105 so that the indicatorlight source 126 is directly viewable to a user (e.g., through a windowin the housing 126). Additionally, the light pipe 126 may illuminate alogo or other symbol (e.g., a battery symbol) on the eraser 100. In someembodiments, an aural indicator (e.g., a buzzer, speaker, etc.) (notshown) may be included instead of, or in addition to, the indicatorlight source.

As described, each of the rechargeable stylus 16 and the rechargeableeraser 100 cooperate with the charging station 18 to recharge therespective power sources 52 and 116. FIG. 5 illustrates an embodiment200 of the charging station 18. In the depicted embodiment, one or moreof the styli 16, and the eraser 100, may cooperate with the chargingstation 200 to charge the respective power sources 52 and 116 of the oneor more styli 16 and the eraser 100, as described in further detailbelow. The charging station 200 includes one or more stylus receptacles202 for recharging the rechargeable styli 16. While FIG. 5 depicts anembodiment with four stylus receptacles 202, the charging station 200may include a single stylus receptacle 202 or may otherwise include moreor less than four stylus receptacles 202. Additionally, the chargingstation 200 may or may not include an eraser receptacle 204 forrecharging the rechargeable eraser 100. The charging station 200preferably has a generally rectangular top face 206, and the variousreceptacles 202 and 204 are preferably disposed within the top face 206such that a top edge 208 of each receptacle 202, 204 is coplanar withthe top face 206. The top face 206 and styli receptacles 202 maycooperate to form a plurality of depressions 210, which may facilitategrasping and removal of the styli 16 from the receptacles 202. In asimilar manner, a depression 212 may facilitate grasping and removal ofthe eraser 100 from the receptacle 204. A back face 214 intersects thetop face 206, and extends downward from the top face 206. The back face214 is preferably planar, allowing the back face 214 to mount flushagainst another planar surface such as the writing surface 14, asdepicted in FIG. 1A.

Each of the stylus receptacles 202 is preferably formed such that theshape of the receptacle 202 is generally complementary to the shape ofthe stylus 16. For example, the receptacles 202 illustrated in FIG. 5have a shape generally complementary to the stylus 16. That is, eachreceptacle 202 is a horizontally-extending elongated groove or channel211 with a generally curvilinear cross section 213 complementary to thegenerally cylindrical shape of the illustrated stylus 16. FIG. 5 depictsan embodiment in which the channels 211 of each of the stylusreceptacles 202 are at an incline 215 such that an end 209A of eachreceptacle 202 is at a greater depth below the plane of the top surface206 than an end 209B of each receptacle 202. This is further depicted inFIG. 6A. The incline 215 may, in addition to the depressions 210, aid ingrasping and removing the stylus 16 from the receptacle 202. Of course,it will be apparent that, while in some embodiments the channel 211 hasa curvilinear cross-section 213 and is at an incline 215 with regard tothe plane of the top surface 206, as depicted in FIG. 6B, the channel211 could also have a rectangular cross-section, as depicted in FIG. 6C,or any other desirable cross-section. Moreover, the channel 211 may havemore or less of an incline 215 and, in fact, need not have an incline215 at all.

While the shape of the channels 211 of each of the stylus receptacles202 is described as complementary to the shape of the stylus 16, it isworth noting that there is no feature of the receptacles 202 that actsagainst removal of the stylus 16 from the channel 211. Thus, if thecharging station 200 were turned upside-down (or even so that the topface 206 were perpendicular to the ground, each stylus 16 would simplyfall out of its respective receptacle 202. The lack of any retentionmechanism within the receptacle 202 (or the receptacle 204) promotesusage thereof, because this permits a user to place or remove the stylus16 (or the eraser 100) in the receptacle 202 (or 204) without requiringany additional force, and permits the user to use the charging station200 just as the user would use a marker tray on a dry erase board, or achalk tray on a chalk board.

FIG. 7 depicts a top plan view of the charging station 200 in FIG. 5. AsFIG. 7 illustrates, the back face 214 includes two arrays 216 of magnetsfor adhering the back face 214 of the charging station 200 to a metallicsurface such as the writing surface 14. Of course, other methods ofadhering the charging station 200 to a surface could also be employed,such as suction cups, clamps, adhesive tape, glue, hook-and-loopmaterial, etc., depending on the surface to which the charging station200 is to be adhered.

The top plan view FIG. 7 also illustrates each of the styli receptacles202 having two sets of charging contacts 218 and 220. In the depictedembodiment, the charging contacts 218 include two contacts 218A and2188, while the charging contacts 220 include two contacts 220A and220B. Each pair of contacts 218, 220 is disposed within the receptacle202 and arranged to contact the corresponding charging rings 60 and 62disposed on the stylus 16. As depicted in FIG. 7, in one embodiment eachset of charging contacts 218 and 220 protrudes through a pair ofopenings 221 in the surface 222 of the receptacle 202. Each of thecontacts 218A and 218B and each of the contacts 220A and 220B may beelectrically and physically connected to each other as depicted in FIGS.8A and 8B. In one embodiment, depicted in FIG. 8A, each of the contacts218A and 218B, and each of the contacts 220A and 220B, is formed on anarc-shaped metallic band 224. In this manner, the arc shape of themetallic band 224 is complementary to the underside of the channel 211,allowing the contacts 218 and 220 to protrude through the openings 221in the surface 222 of the channel 211 forming the receptacle 202. Inanother embodiment, depicted in FIG. 8B, each of the contacts 218A and218B, and each of the contacts 220A and 220B, is formed on (or as partof) a metallic plate 226 approximately twice the width of the contact.The pair of metallic plates 226 for the set 218 or the set 220 ofcontacts are electrically connected to each other by a metallic strip228 stamped (or otherwise formed) into a “V” shape such that thecontacts 218 and the contacts 220 protrude through the openings 221 inthe surface 222 of the channel 211 forming the receptacle 202. As alsodepicted in FIGS. 8A and 8B, the openings 221 in the surface 222 may besurrounded on the underside of the channel 211 by a recessed area 223,to facilitate fitting engagement of the metallic band 224 or themetallic plate 226 with the underside of the channel 211 and preventlateral or radial movement of the contacts 218 and 220.

Each configuration of contacts depicted in FIGS. 8A and 8B may providean additional advantage to the disclosed charging system 10. Themetallic band 224 and the metallic strip 228 may each be formed suchthat they provide a spring force against the channel 211 when assembledso that the contacts 218 or 220 protrude through the openings 221 in thesurface 222 of the channel 211. This arrangement provides a distinctadvantage in that the metallic band 224 and/or the metallic strip 228may be formed so the spring force is slightly less than the force of thestylus 16 against the contacts 218 and 220 when acted on by gravity. Byso configuring the band 224 and/or the strip 228, the contacts 218 and220 can be configured to retreat slightly through the opening 221 asthey come into contact with the charging contacts 60 and 62 on thestylus 16, allowing the stylus to lower slightly into receptacle 202while still maintaining contact between the charging contacts 60 and 62.Thus, as the stylus 16 is lowered into the receptacle 202, the chargingcontacts 218 and 220 move slightly along the charging contacts 60 and62. This “swiping” movement may facilitate better conductivity betweenthe contacts 218 and 220 and the respective charging contacts 62 and 60by clearing debris or other fouling of the contacts or rings that mayotherwise interfere between the two.

Referring again to FIG. 7, the top plan view also illustrates the eraserreceptacle 204 having a set of charging contacts 230 and 232. Thecharging contacts 230 and 232 are disposed within the receptacle 204 andarranged to contact the corresponding charging contacts 122 and 124 onthe rechargeable eraser 100. Similar to the charging contacts 218 and220 in the stylus receptacles 202, in one embodiment the chargingcontacts 230 and 232 protrude through a pair of openings 231 in thesurface 234 of the receptacle 204. While the embodiment depicted in FIG.7 includes only a single contact 230 or 232 for each of thecorresponding charging rings 122 and 124 on the rechargeable eraser 100,alternate embodiments may employ arrangements of two or more contacts230 or 232, similar to the arrangement of two contacts 218 or twocontacts 220 employed in the embodiment of the receptacles 202 depictedin FIG. 7.

Referring now to FIGS. 9A and 9B, an illustrated embodiment includes astylus 240 and a receptacle 242 having generally corresponding formfactors. For example, FIG. 9A depicts the stylus 240 including a firstportion 244A, a second portion 246A, and mid-portion 248A. Each of thefirst and second portions 244A and 246A, respectively, is depicted asbeing wider, in general, than the mid-portion 248A. FIG. 9B similarlydepicts the receptacle 242 including a first portion 244B generallycorresponding in size and shape to the portion 244A of the stylus 240, asecond portion 246B generally corresponding in size and shape to theportion 246B of the stylus 240, and a mid-portion 248B generallycorresponding in size and shape to the portion 248A of the stylus 240.The charging contacts 60 and 62 on the stylus 240 are configured toalign with the corresponding charging contacts 220 and 218,respectively, on the receptacle 242 when the stylus 240 is rested in thereceptacle 242. Moreover, the lack of a retention mechanism facilitateseffortless placement of the stylus 240 in, and removal of the stylus 240from, the receptacle 242. The depressions 210 in the mid-portion 248B ofthe receptacle 242, aid in grasping the stylus 240 to remove it from thereceptacle 242. It should be apparent both from the respective shapes ofthe stylus 240 and the receptacle 242, and from the respectiveplacements of the charging contacts 60 and 62 and the charging contacts218 and 220, that the stylus 240 and the receptacle 242 must be orientedas depicted by FIGS. 9A and 9B if the stylus 240 and the receptacle 242are to cooperate to charge the rechargeable power source 52.

FIGS. 10A, 10B, and 10C illustrate an alternate embodiment of the system10, in which a receptacle 250 (FIG. 10B) may cooperate with a stylus 252(FIGS. 10A and 10C) to charge the stylus 252 regardless of theorientation of the stylus 252 when resting in the receptacle 250. Inthis alternate embodiment, the receptacle 250 includes three sets ofcharging contacts 254. A first set of charging contacts 254A is disposedat the midpoint of the length of the receptacle 250, while second andthird sets of charging contacts 254B and 254C, respectively, are eachdisposed at a distance, D2, along the length of the receptacle 250 fromthe first set of charging contacts 254A. The charging contacts 254 areelectrically connected to a power source (not shown) such that thecharging contacts 254A are connected to one of “power” or “ground,”while the charging contacts 254B and 254C are connected to the other of“power” or “ground.”

The stylus 252 includes two charging contacts 256A and 256B. Thecharging contact 256A corresponds electrically (i.e., is the same one of“power” or “ground”) to the charging contacts 254A, and is disposed atthe midpoint of the length of the stylus 252 so that it aligns with thecharging contacts 254A when placed in the receptacle 250. The chargingcontact 256B corresponds electrically to the charging contacts 254B and254C, and is disposed at the same distance, D2, from the chargingcontact 256A so that it aligns with either the set of contacts 254C (asdepicted in FIG. 10A) or the set of contacts 254B (as depicted in FIG.100). In this manner, the stylus 252 may be placed in the receptacle 250in either of the orientations shown in FIGS. 10A and 100, while stillcooperating with the charging station 200 to charge the rechargeablepower source 52.

FIGS. 11A, 11B, and 110 illustrate yet another embodiment of the system10, in which a receptacle 260 (FIG. 11B) may cooperate with a stylus 262(FIGS. 11A and 110) to charge the stylus 262 regardless of theorientation of the stylus 262 when resting in the receptacle 260. Inthis embodiment, each receptacle includes two sets of charging contacts264. A first set of charging contacts 264A is disposed at a distance,D3, from a first end 266 of the receptacle 260, while a second set ofcharging contacts 264B is disposed at the same distance, D3, from asecond end 268 of the receptacle 260. A charging circuit (not shown)electrically connects the charging contacts 264 to a power source (notshown) such that each set of charging contacts 264 may be connectedeither to “power” or to “ground,” according to the orientation of thestylus 262 in the receptacle 260. A simple diode bridge is one chargingcircuit, known to those of ordinary skill in the art, that wouldaccomplish this reversible polarity feature.

The stylus 262 includes two charging contacts 270A and 270B. Each of thecharging contacts 270A and 270B may correspond electrically to either“power” or “ground” (so long as one contact 270 is connected to each),and is disposed at the distance, D3, a respective end 272 or 274 of thestylus 262. The charging circuit acts to align the two sets of chargingcontacts 264A and 264B on the receptacle 260 with the charging contacts270A and 270B on the stylus 260. For example, suppose that the chargingcontact 270A is connected to the “power” terminal of the rechargeablepower source 52, and that the charging contact 270B is connected to the“ground” terminal of the rechargeable power source 52. The chargingcircuit would act to align the relative polarities of the sets ofcharging contacts 264A and 264B such that, when the stylus 262 is placedin the receptacle 260 as depicted in FIGS. 11A and 11B, respectively,the set of charging contacts 264A connects to “power” while the set ofcharging contacts 264B connects to “ground.” Likewise, when the stylus262 is placed in the receptacle 260 as depicted in FIGS. 11C and 11B,respectively, the charging circuit would act to align the relativepolarities of the sets of charging contacts 264A and 264B such that theset of charging contacts 264A connects to “ground” while the set ofcharging contacts 264B connects to “power.” In this manner, the stylus262 may be placed in the receptacle 260 in either of the orientationsshown in FIGS. 11A and 11C, while still cooperating with the chargingstation 200 to charge the rechargeable power source 52.

It should be understood that in the embodiment described with referenceto FIGS. 10A, 10B, and 10C, it need not be the receptacle 250 that hasthree sets of charging contacts 254. Instead, the stylus 252 could havethree charging contacts 256, while the receptacle 250 includes only twosets of charging contacts 254. Likewise, it should also be understoodthat in the embodiment described with reference to FIGS. 11A, 11B, and11C, the charging circuit may electrically connect the charging contacts270 on the stylus 262 to the rechargeable power source 52, while each ofthe two sets of charging contacts 264 on the receptacle 260 is connectedto either “power” or “ground” (so long as one set of charging contacts264 is connected to each).

As described above, the stylus 16 may also be a mouse operating inalmost all regards similar to the styli 16 described with reference toFIG. 2, but having a non-marking writing element 28, and having someadditional functionality. FIG. 12 depicts one embodiment of a mousestylus 280 that, in addition to a non-marking writing element 28, alsoincludes buttons 282 and 284, which may function as left and right mousebuttons, respectively. The mouse stylus 280 may also include one or morebuttons 286 for activating features of associated software, performingmacro operations, etc. Of course, the activation of any of the buttons282, 284, or 286 may be communicated to a connected computer system (notshown) through the TCU 12 using the infrared signal to indicate to theTCU 12 that a user pressed the button 282, 284, or 286, or may becommunicated directly to the connected computer system by anotherwireless means (e.g., wireless USB, Bluetooth®, etc.).

With reference now to FIG. 13, in some embodiments, a TCU 290 mayinclude one or more charging circuits for charging a stylus device 292,which may be a stylus device such as the stylus 16, having a writingimplement, or a stylus device such as the mouse stylus 280. In theembodiment depicted in FIG. 13, the stylus device 292 includes at leasta body 293 generally symmetrical about a lengthwise axis A, the one ormore transmitters (e.g., an IR transmitter and an ultrasonictransmitter) (not shown), and the rechargeable power source (housed inthe stylus body) for powering the transmitters. A stylus side couplingcircuit may include charging elements 294 electrically coupled to therechargeable power source. The charging elements 294 may be metallicrings coaxial with the lengthwise axis of the stylus body 293, asdepicted in FIG. 13, however the charging elements 294 need not bering-shaped. Of course, the charging elements 294 may be disposedanywhere on the body 293 of the stylus device 292 so as to cooperatewith a mobile device-side coupling circuit on the TCU 290 to charge therechargeable power source.

As described above, the TCU 290 may include appropriate receivers (e.g.IR and ultrasonic receivers) for receiving signals transmitted by thestylus device 292, a processor, a memory, and a communication port (notshown) for facilitating communication between the TCU 290 and a computersystem (not shown). Additionally, the TCU 290 may include a mobiledevice-side coupling circuit. The mobile device-side coupling circuitmay include charging contacts 296 electrically coupled to a chargingpower source. The charging contacts 296 may be metallic and need nothave any particular shape or location on the TCU 290, so long as thecharging contacts 296 cooperate with the charging elements 294 of thestylus-side coupling circuit on the stylus 292 to charge therechargeable power source.

The embodiment depicted in FIG. 13 includes a groove 298 having a shapecomplementary to the shape of the stylus device 292. The chargingcontacts 296 of the mobile device-side coupling circuit are disposed inthe groove 298 to cooperate with the charging elements 294 of thestylus-side coupling circuit on the stylus device 292. The stylus device292 may be held in place near the TCU 290 and/or the stylus-sidecoupling circuit may be aligned with the mobile device-side couplingcircuit by operation of one or more magnetic materials. For example, thecharging elements 294 on the stylus device 292 and/or the chargingcontacts 296 on the TCU 290 may be magnetized. Alternatively oradditionally, a magnet may be disposed within one or both of the stylusdevice 292 and the TCU 290. In some embodiments, a ring 300, adapted toreceive an end of the stylus device 292, may be mounted on or formed inthe TCU 290 for retaining and/or aligning the stylus device 292 with theTCU 290. For example, the ring 300 may be mounted at an end 302 of thegroove 298, as depicted in FIG. 13. The ring 300 may also, in someembodiments, operate as a charging contact of the mobile device-sidecoupling circuit, replacing, for example, one of the charging contacts296. Of course, some embodiments may omit one or more of the groove 298(as described below with respect to FIG. 15), the ring 300, and themagnetic material.

FIG. 14A illustrates one embodiment of a stylus-side coupling circuit304A and a mobile device-side coupling circuit 306A. The stylus-sidecoupling circuit 304A includes a rechargeable power source 305A in thestylus device 292, and the pair of charging elements 294 electricallycoupled to the rechargeable power source 305A. The mobile device-sidecoupling circuit 306A includes corresponding charging contacts 296electrically coupled to a charging power source 307A. When the chargingelements 294 come into contact with the charging contacts 296, themobile device-side coupling circuit 306A cooperates with the stylus-sidecoupling circuit 304A to charge the rechargeable power source 305A. Ofcourse, the stylus-side coupling circuit 304A and the mobile device-sidecoupling circuit 306A may include additional components 312A and 314A,respectively.

FIG. 14B illustrates an alternate embodiment of a stylus-side couplingcircuit 304B and a mobile device-side coupling circuit 306B. The mobiledevice-side coupling circuit 306B includes a primary induction coil 310coupled to a charging power source 307B. The stylus-side chargingcircuit 304B includes a secondary induction coil 308 coupled to arechargeable power source 305B. As readily understood by those ofordinary skill in the art, a charging power supply 307B may cause afirst current flowing through the primary induction coil 310. The firstcurrent will induce a second current in the secondary induction coil 308when the stylus-side coupling circuit 304B is placed proximate to themobile device-side coupling circuit 306B. The second current willoperate to charge a rechargeable power source 305B in the stylus device.Of course, the stylus-side coupling circuit 304B and the mobiledevice-side coupling circuit 306B may include additional components 312Band 314B, respectively.

FIG. 15 illustrates an embodiment of the system in which the TCU 290does not include the groove 298 depicted in FIG. 13. Instead, the ring300 cooperates with the charging contacts 296, which, in thisembodiment, extend from the TCU 290. FIG. 15 depicts the chargingcontacts 296 as curved to complement the ring-like shape of the chargingelements 294.

FIG. 16 illustrates an embodiment of the system in which the TCU 290 mayhave included or attached thereto a receptacle 320 for receiving an endof the stylus device 292 such that placement of the end of the stylus290 into the receptacle 320 will cause the stylus-side coupling circuit304A, 304B and the mobile device-side coupling circuit 306A, 306B tocooperate to charge the rechargeable power source 305A, 305B. Forexample, the receptacle 320 may be shaped as an inkwell, and may includethe mobile device-side coupling circuit 306A or 306B (e.g., the chargingcontacts 296 or the primary induction coil 310). Accordingly, thecharging elements 294 or secondary induction coil 308 of the stylus-sidecoupling circuit 304A or 304B must be arranged in a correspondingmanner.

While the present disclosure describes specific embodiments intended tobe illustrative only, and not limiting, it will be apparent to those ofordinary skill in the art that changes, additions, or deletions may bemade to the disclosed embodiments without departing from the spirit andscope of the disclosure. Moreover, it is explicitly contemplated thateach of the individual features described with reference to the variousembodiments disclosed may be combined with any of the other featuresdisclosed herein. Thus, the intention is to cover all modifications,alternative constructions, and equivalents falling within the spirit andscope of the disclosure as defined by the appended claims.

1. A system comprising: a stylus device comprising: a stylus bodygenerally symmetrical about a lengthwise axis; a first transmitter; asecond transmitter; a rechargeable power source powering the first andsecond transmitters and disposed within the stylus body; a stylus-sidecoupling circuit; and a mobile device comprising: a first receiver; asecond receiver; a communication port; a mobile device-side couplingcircuit; and a charging power source electrically coupled to mobiledevice-side coupling circuit, wherein the mobile device-side couplingcircuit cooperates with the stylus-side coupling circuit to charge therechargeable power source, and wherein one or both of the stylus and themobile device further comprises a magnetic material.
 2. The system ofclaim 1, wherein the mobile device further comprises an elongated grooveformed in the mobile device and having a shape complementary to that ofthe stylus body, and wherein the mobile device-side coupling circuitcooperates with the stylus-side coupling circuit to charge therechargeable power source when the stylus is placed in the groove. 3.The system of claim 1, wherein the mobile device further comprises areceptacle formed to receive an end of the stylus device, and whereinthe mobile device-side coupling circuit cooperates with the stylus-sidecoupling circuit to charge the rechargeable power source when the stylusis placed in the receptacle.
 4. The system of claim 1, wherein: thestylus-side coupling circuit comprises: a first charging elementdisposed on the exterior of the stylus body and electrically coupled toa first terminal of the rechargeable power source; and a second chargingelement disposed on the exterior of the stylus body and electricallycoupled to a second terminal of the rechargeable power source; and themobile device-side coupling circuit comprises: a first charging contactdisposed to align with the first charging element of the stylus; and asecond charging contact disposed to align with the second chargingelement of the stylus.
 5. The system of claim 4, wherein each of thefirst and second charging elements on the stylus device comprises ametallic ring formed around the stylus body about the lengthwise axis.6. The system of claim 1, wherein: the mobile device-side couplingcircuit comprises a primary induction coil; the stylus-side couplingcircuit comprises: a secondary induction coil; and a first currentflowing through the primary induction coil induces a second current inthe secondary induction coil when the stylus device is coupled with themobile device.
 7. (canceled)
 8. The system of claim 1, wherein themagnetic material aligns the stylus device with the mobile device suchthat the mobile device-side coupling circuit cooperates with thestylus-side device coupling circuit to charge the rechargeable powersource.
 9. The system of claim 1, wherein the magnetic material retainsthe position of the stylus device such that the mobile-device sidecoupling circuit remains coupled with the stylus-side coupling circuit.10. The system of any of claim 1, wherein the mobile device furthercomprises a ring mounted on the mobile device at an end of the elongatedgroove, the ring having a central opening operable to receive an end ofthe stylus.
 11. The system of claim 10, wherein the ring comprises aportion of the mobile device-side coupling circuit. 12-164. (canceled)165. A stylus comprising: a stylus body generally symmetrical about alengthwise axis; a first transmitter; a second transmitter; arechargeable power source powering the first and second transmitters anddisposed within the stylus body; a stylus-side coupling circuit operableto couple the rechargeable power source to a recharging power supply;and a magnetic material disposed to cooperate with a mobile device tomaintain a position of the stylus-side coupling circuit with respect tothe mobile device.
 166. The stylus of claim 165, wherein a contact ofthe stylus-side coupling circuit comprises the magnetic material. 167.The stylus of claim 165, wherein a contact of the stylus-side couplingcircuit comprises a ring coaxial with the lengthwise axis.
 168. Thestylus of claim 165, wherein the stylus-side coupling circuit comprisesan induction coil, and wherein the magnetic material is disposed toalign the induction coil with a corresponding induction coil in themobile device.
 169. The stylus of claim 165, further comprising anerasable writing element operable to mark a surface while each of thefirst and second transmitters transmit respective signals.
 170. A mobiledevice comprising: an infrared receiver; a radio frequency receiver; acommunication port; a charging power source; a mobile device-sidecoupling circuit operable to couple the charging power source to arechargeable power source in a stylus device; and a magnetic materialdisposed to cooperate with the stylus device to maintain a position ofthe stylus with respect to the mobile device-side coupling circuit. 171.The mobile device of claim 170, wherein a contact of the mobiledevice-side coupling circuit comprises the magnetic material.
 172. Themobile device of claim 170, wherein the mobile device-side couplingcircuit comprises an induction coil, and wherein the magnetic materialis disposed to align the induction coil with a corresponding inductioncoil in the stylus.
 173. The mobile device of claim 170, furthercomprising a ring mounted on the mobile device, the ring having acentral opening adapted to receive an end of the stylus.
 174. The mobiledevice of claim 170, further comprising an elongated groove having ashape complementary to that of the stylus, wherein the mobiledevice-side coupling circuit cooperates with a corresponding stylus-sidecoupling circuit to charge the rechargeable power source when the stylusis placed in the groove.